1. Field of the Invention
This invention relates to a suspension controller for a vehicle, and more particularly to a suspension controller for effectively absorbing sporadic shocks to a vehicle body, caused by the wheels' riding-over a bump or riding-through a dip in a road surface.
2. Discussion of the Prior Art
In order to reduce shocks to a vehicle body depending upon the road condition and running condition of the vehicle, and furthermore to keep good control and high stability of the vehicle, various suspension controllers have been proposed. The suspension controller controls a suspension system, installed between a body and wheels, by altering the spring constant, damping force, bush characteristic, stabilizer characteristic or the like. For example, the following suspension controllers have been provided: one which controls a suspension system by altering the spring constant of the air spring of the suspension system in response to road condition (Japanese Published Unexamined Patent Application No. Sho-59-26638); one by altering both of the spring constant of the air spring and the damping force of the shock absorber (Japanese Published Unexamined Patent Application No. Sho-59-23712); one by altering only the damping force of the shock absorber (Japanese Published Unexamined Patent Application No. Sho-58-30542); one by altering the vehicle height (Japanese Published Unexamined Patent Application No. Sho-59-23713); one by altering the bush characteristic (Japanese Published Unexamined Utility Model Application No. Sho-59-132408); and one by altering the stabilizer characteristic (Japanese Published Unexamined Utility Model Applications Nos. Sho-59-129613 and Sho-59-135213).
When a vehicle height sensor detects that the vehicle is continuously running on a rough road or when a brake lamp switch or a throttle position sensor judges that a nose dive or a nose up is going to occur, the above-mentioned suspension controllers alter various characteristics of the suspension system so as to maintain good control and high stability in continuous rough road running or so as to prevent the subsequent nose dive or nose up.